java - Do we need an interface/contract if we cannot generalize method parameters -

i want create interface having 2 methods, uploadfile , downloadfile. while need implementors implement these 2 methods, not sure , want care arguements these methods need take. mean, different implementors may ask different parameters. in case, should still go ahead creating interface making above methods var-arg methods, below

boolean uploadfile(object ... parameters) outputstream downloadfile(object ... parameters) 

or there better approach this? right create interface if cannot generalize method parameters? sure method names , return types.

this might use case generics. consider following arrangement of classes - here define abstract "parameter" type , reference in interface. concrete classes work particular parameter set.

abstract class handlerparams {     }         interface filehandler<t extends handlerparams> {   boolean uploadfile(t parameters);   outputstream downloadfile(t parameters); } 

example implementations:

class urlparams extends handlerparams {   // whatever... }    class urlfilehandler implements filehandler<urlparams> {    @override   public boolean uploadfile(urlparams parameters) {     // ...   }    @override   public outputstream downloadfile(urlparams parameters) {     // ...   }     } 

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i must admit, i'm struggling imagine scenarios arrangement helpful. suppose have works file handlers, feels little artificial:

class somethingthatusesfilehandlers {   public <t extends handlerparams> void dosomething(filehandler<t> handler,       t params) {     handler.downloadfile(params);   } }